Green et al U.S. Pat. No. 4,412,903 describes a diamondlike carbon coating deposited from methane in a direct current glow discharge process. The substrate may be precleaned with argon ion bombardment. Carlson et al U.S. Pat. No. 4,060,660 also refers to the deposition of an amorphous carbon thin-film in a glow discharge process.
Cuomo et al U.S. Pat. No. 4,351,712 is concerned with a low energy ion beam deposition/oxidation process. The deposition takes place at low energy levels from about 30 eV to about 180 eV. Banks U.S. Pat. No. 4,437,962 is directed to the production of diamondlike flakes which are mixed with a binder or matrix material to form composites.